There are many locations which are inaccessible by railroad or boat that require large quantities of supplies in order to be livable, and/or which have natural resources that are difficult to move to other areas of the world. In such places particularly it would be desirable to have a land train, that could move over natural terrain (that is without the need for train tracks) so that a large quantity of material could be moved at a time, as compared with the inefficient technique driving individual trucks. However, there are practical difficulties associated with such overland trains, perhaps the foremost of which is the difficulty of steering the train. If an overland train is long enough so that it obtains close to optimum efficiency in the transport of goods or passengers, then it is very difficult to make the rear end of the train follow the front end in moving over dirt or gravel roads, or bare earth or sand, or snow covered land, given the normal unevenness of terrain. Such land trains virtually universally need to move in a path that is at least somewhat serpentine, meaning that it is almost impossible using present technology to get the rear car to track (follow the same path as) the lead car.
According to the present invention a self tracking land vehicle is provided which can effectively be used in almost any terrain except actual mountains. The land train according to the invention is particularly effective at transporting cargo since each car of the train may include a standardized container mounted on a chassis, the standardized containers being readily loadable onto and unloadable from the chassis. A key to making the train self tracking is to provide only the front axle or axles as pivotal about a substantially vertical axis, for each of the cars, and to space all of the axles of all of the cars in the train substantially the same effective longitudinal distance. It is also desirable to provide a substantially transversely rigid (that is a horizontal dimension substantially perpendicular to the longitudinal dimension) connection of the front of each car to the rear of the car in front of it.
According to one aspect of the present invention, a self tracking land vehicle is provided comprising the following components: At least four cars, each car having a front end, a rear end, a bottom, and a top, and extending from the front end to the rear end in a generally horizontal longitudinal dimension. Each car having at least first and second axles with at least two inflatable tires each associated with each of the axles. The first axle associated with each car mounted closer to the front end than the rear end of the car, and mounted for pivotal movement about a substantially vertical axis with respect to the car bottom. The second axle associated with each car mounted closer to the rear end than the front end, and the second axle mounted with respect to the car bottom so that it cannot pivot about a substantially vertical axis. A substantially transversely rigid connection from the front end of each first axle of each car to the rear end of a leading car so that the cars are connected together in a land train. Each car and associated transversely rigid connection of the train have substantially the same length. And all of the axles of all of the cars spaced from each other at a substantially uniform effective longitudinal distance apart so that the land train is self-tracking, all of the cars substantially precisely following the same path of movement.
A motor or engine may be provided for powering at least one axle of each car so that all of the cars are driven. Typically a lead drive car is also provided. The lead drive car has a front end with at least one steerable axle with at least two inflatable tires adjacent the front end, and a rear end, and at least one non-steerable axle adjacent the rear end, the non-steerable axle mounted with respect to the drive car so that it cannot pivot about a substantially vertical axis. Preferably a power plant (such as a diesel engine) is provided in the drive car for producing electricity. An electric motor is provided for at least some of the cars for driving at least one axle of those cars, the electric motors receiving electrical energy from the power plant.
Typically the first and second axles each comprise a pair of ganged axles, and include a center point. Then the center points of all of the axles are spaced from each other substantially the same longitudinal distance.
The substantially transversely rigid connection between the cars preferably allows limited vertical relative movement, and pivotal relative movement about a longitudinal central axis, of each car with respect to the preceding car. For example, the connection comprises the following components: two transversely spaced clevis assemblies mounted to each car, and a hinge pin associated with each clevis assembly; a swivel pin; first and second swivel bushings operatively connected to the swivel pin; and first and second wishbone assemblies each operatively connecting a swivel bushing to two hinge pins, so that the cars may move vertically with respect to each other by pivotal movement about the hinge pins, and may move pivotally with respect to each other by pivotal movement of the swivel bushings with respect to each other. Also, thrust washers and plates preferably engage each swivel bushing, and swivel nuts are provided for holding the swivel bushings on the swivel pin.
Typically the land train comprises at least eight cars, such as ten or twelve cars, and a standardized 20 foot container is mounted on top of a plurality of the cars (such as all of the cars except for the drive car if a cargo land train). If additional power is necessary one of the cars of the train spaced from the drive car may have another power plant therein, or the drive car may have space for cargo and passengers and the power plant provided in another car.
According to another aspect of the present invention, a car for a self tracking land vehicle is provided. The car comprises the following components: A chassis having a front end, rear end, bottom, and top, and extending from the front end to the rear end in a generally horizontal longitudinal dimension. A standardized container mounted on the chassis top. At least first and second axles with at least two inflatable tires each associated with the chassis. The first axle mounted closer to the front end than the rear end of the chassis, and mounted on an assembly for pivotal movement about a substantially vertical axis with respect to the chassis bottom. The second axle mounted closer to the rear end than the front end, and the second axle mounted with respect to the chassis bottom so that it cannot pivot about a substantially vertical axis. A substantially transversely rigid connection extending outwardly from the first axle assembly past the front end of the chassis. And a motor or engine mounted to the chassis for driving at least one of the axles.
The chassis and the container are preferably each about 20 feet long, and the effective spacing between the first and second axles is about 7 to 9 feet (e.g. 8 feet) and the connection extends longitudinally about 3 to 5 feet (preferably about 4 feet) from the axle pivot.
According to another aspect of the present invention a method of transporting cargo or passengers over land in a train, such as described above, is provided. The method comprises the steps of: (a) connecting the at least four cars together in a land train so that the front axle at the front end of each car, except the lead car, is connected to the rear end of the preceding car by a substantially transversely rigid connection, and so that each axle of each car is spaced substantially the effective longitudinal spacing x from the next axle; and (b) powering (e.g. pulling) the front end of the first car over land in an at least somewhat serpentine path so that the inflatable tires of each car substantially precisely self-track in the path of the inflatable tires of the preceding car.
Preferably step (b) is practiced by connecting the front end of the leading car of the land train to the rear end of a drive car, the drive car having a rear axle with inflatable tires spaced from the front axle of the leading cargo or passenger car substantially the effective longitudinal spacing x, and the drive car having steerable front inflatable tires; and by steering the drive car. Typically the land train has at least eight passenger or cargo cars, and the method comprises the further step of driving at least some of the axles of cargo or passenger cars to facilitate movement of the land train over land. Typically at least some of the cars are cargo cars having a standard transport container mounted on the top thereof; and preferably the method also comprises the further step of loading and unloading cargo from the train by lifting the container onto, or off of, respectively, the car top.
Step (a) is typically practiced to allow limited vertical relative movement, and pivotal relative movement about a longitudinal central axis, of each car with respect to the preceding car. The drive car typically includes a power plant for producing electricity, and only some of the passenger and cargo cars have electric motors for driving an axle or axles thereof; and the method comprises the further step of supplying electricity from the power plant to the electric motors of the passenger and cargo cars to drive an axle or axles thereof.
It is the primary object of the present invention to provide a structure and method for effectively transporting cargo or passengers over land, including natural terrain, in a self tracking train. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.